EFFECTS OF HEAVY METALS IN GROWTH OF TIGER PRAWN, PENAEUS MONODON (FABR.1798)-AN EFFECTIVE ASSESMENT TOOL

Postlarval stages of Penaeus monodon were exposed to cadmium, copper, lead and zinc concentrations under chronic toxicity test (static renewal-30 days) to study the alterations in the growth pattern. Heavy metal exposures produced significant (P<0.01) effect on weight and length. The difference in the relation between the condition factor and geometric increase in the concentration was significant (P<0.01, 0.001). Lower concentrations of cadmium, copper, lead and zinc were enough to produce a significant effect of decreased growth in P.monodon. Significant (P<0.001) reduced growth was observed in 13, 21, 34 and 54 μg/l copper concentrations. P.monodon exposed to lead in 21, 34 and 54 μg/l showed a significant (P<0.05) reduction in growth. High significance (P<0.001) was found in P.monodon exposed to 76 μg/l of zinc concentration. Significance (P<0.05 and P<0.01) was also found for 34 and 51 μg/l Zn in relation to growth. Hence, lower concentrations of cadmium, copper, lead and zinc are enough to produce a significant effect on the growth pattern of Penaeus monodon.